Progress Towards an Enantiospecific Synthesis of a Taccalonolide-like Steroid Skeleton

Abstract

Total synthesis has emerged as a leading strategy to access medicinally-relevant natural products minimally available by isolation. Among natural product classes, steroids stand out for their variety of therapeutic effects. Recent studies have elucidated the structure of “taccalonolides,” a family of heavily functionalized, complex steroids with intriguing chemotherapeutic activity. The Sorensen group is interested in becoming the first to synthesize a taccalonolide in full. This thesis aims to employ principles of Diversity-Oriented Synthesis to produce a steroid with powerful functional group handles that permit access to bioactive taccalonolide-like derivatives. We envision a Michael Addition cascade with a previously unreported epoxide-opening terminating step could establish the taccalonolide-like trans-hydrindane system while building much of the steroid’s complexity. This strategy features the use of biocatalysis, organometallic substitution, and materials from the chiral pool to ensure enantiomeric control. So far, results have produced and isolated a cyclopentene precursor to the desired epoxide-containing fragment with two critical stereocenters set, ensuring stereocontrol in future steps.